Lubricating oil



UNITED STATES PATENT OFFICE LUBRIGATING on.

Charles M. Blair, Jr., Webster Groves, Mo., assignor to PetroliteCorporation, Ltd., Wilmington, Del., a corporation of Delaware NoDrawing. Original application May 31, 1944,

Serial No. 489,238. Divided and this application February 2-1, 1944,Serial No. 523,350

Claims.

This application is a division of my pending application Serial No.489,238, filed May 31, 1943,

and relates to an improved lubricating oil.

In my parent application for patent above recontaining less than 10carbon atoms, such as the examples just recited. Because of theiravailability, relatively low cost, and marked reactivity, maleicanhydride, fumaric acid, and

ferred to I have disclosed a new type of polyester 5 citraconicanhydride, are especially useful, and products of high molecularweight-consisting of products obtained with these reactants will bepolyesters of a resinous or semi-resinous charused below to illustratethe present invention. acter, that can be produced or prepared by anAlcohol reactants of class (2), above, which esterification reaction inwhich two different are suitable for use in preparing the present typesof alcohols enter into combination with a 1 products, are the aliphaticand cycloaliphatic polybasic afi unsaturated, carboxylic acid oranmonohydric alcohols in which the ethylenic carhydride. The two typesof alcohols consist of: hen atom nearest to the hydroxyl group is sepa-(a) Unsaturated aliphatic or cyclo-aliphatic rated from the carbon atomattached to said alcohols; and hydrcxyl group by at least three singlybonded (b) Saturated long chain aliphatic alcohols. carbon atoms. Suchalcohols may contain one My present invention consists of a new comormore carbon-to-carbon double bonds, but all position composed of orcomprising a relatively must satisfy the above requirement as toproxsmall amount of a condensation polymer of the imity to the hydroxylgroup. When the alcohol kind described in my parent application abovecontains two or more. double bonds, these may referred to,andalubricating oil. be either conjugated or non-conjugated. My In myco-pending application Serial No, preferred class of unsaturatedaliphatic and 489,237, filed May 31, 1943, there are describedcycloaliphatic alcohols is composed of those havcertain new polymerizedesters which are preins 8 Or mo e a bo t s a e s than 32 pared fromunsaturated aliphatic or cyclecarbon atoms), and are exemplified by thefolaliphatic alcohols and of! unsaturated, carboxylic lowing:Octene-3-ol-8, decene-1-ol-10, oleyl alcoacidsin approximately equimolalquantities. The hol, erucylalcohol, linoleyl alcohol, eicosene-lO-compounds used in the new composition of matol-l, p-vinyl cyclohexanol,citronellal, rhodinol, ter constituting my present invention may beabietyl alcohol, dihydroabietyl alcohol, crude looked upon as beingderived from certain of the 'spefln oil alcohols, crude jojoba oilalcohols, and compounds of my said co-pending application the like.Serial No. 489,237. Specifically, they may be Alcohol reactants of class(3), above, which looked upon as being the most complete esters aresuitable for preparing products of the presof polymerized acidicfractional esters derived by ent invention, are the saturated aliphaticor condensing a 'polybasic afi unsaturated acid (or alkylcycloaliphaticalcohols containing 8 or more anhydride) with approximately an equimolalcarbonatoms and less than 32 carbon atoms, and quantity of anunsaturated aliphatic or cyclopreferably, the normal, primary alcoholsconaliphatic alcohol, the alcohol used to form the e taining 8 or morecarbon atoms. Examples of final esters being a saturated aliphaticalcohol. suitable alcohols are: 2-ethyl hexanol, S-ethyl- The compoundsemployed in my herein denon'anol-2, 7-ethyl-2-methylundecanol,3,9-discribed new composition may, perhaps, be best 40ethyltridecanol-fi, and the like. Examples of the described in terms ofa method of preparation. most preferred alcohols are: n-octanol, n-deca-The required reactants are: n01, lauryl alcohol, myristic alcohol, cetylalcohol, (1) A polybasic (including dibasic) as unsatstearyl alcohol,l-eicosanol, l-docosanol. Other urated, carboxylic acid or anhydride;useable alcohols include propylcyclohexanol, oc-

(2) An unsaturated aliphatic or cyclo-aliphatic 4r) tylcyclohexanol,decylcyclohexanol, etc. alcohol; and One method of preparingthe newproducts used (3) A saturated, long chain aliphatic or alkyl i the mosition constituting my present in- W phatic alcohol. vention, is to mixthe three desired reactants The total mo s of v( d d u of the kindsdescribed above in the desired proappr im t y equal the quivalents of(1) with portions, keeping these proportions within the respect tocarboxylic acid g p Whi e the ratio limitspreviously specified. Thismixture is then of moles of (2) to moles of (3'). y v ry from heated andstirred at a temperature in the range about 0.2 to 5.0. y from about 100C. to about 250 C. for a period Examples of suitable reactants of class(1), of several hours. The-exact temperatures and above, are upunsaturated, carboxylic acids and heating periods employed will dependupon the anhydrides, such as: maleic acid, fumaric acid, specificreactants employed. as well-as upon the citraconic acid, aconitic acid,itaconic acid, mesuse to whichthe product is to be'put. During aconicacid, maleic anhydride, citraconic anhythe heating period the viscosityand average modride, itaconic anhydride, and the like. Thepre lecularweight of the product increase. For cerferred class of acids andanhydrides are those tain purposes, as for use as a pour pointdepressant for lubricating oils, a material 'of average molecular weightin the range of 1,200 t 5,000 may be desirable; so the reaction may bestopped 1 'Although the present compounds may be prepared by reacting attemperatures of from about 100 C. to about 250 0., I- generally preferto carry out the reaction in the temperature range from about 150 C. toabout 210 C. The reaction.

involved is notcompletely understood, but appears to involve bothesteriflcation and addition of the unsaturated constituents.Conventional esteriflcation catalysts such as sulfuric acid, betacamphor sulfonic acid, para toluene sulfonic acid,

hydrochloric acid, etc., may be employed. Alsoolefine condensationcatalysts such as sulfuric acid, benzoyl peroxide, hydrogen peroxide,etc., may also be employed. However, none of these catalysts isnecessary for preparation of the compounds,'as appreciable reaction andpolymerization may, be obtained simply by heating the reactants at theproper temperature for a period of several hours. To obtain the highestrate of reaction and polymerization, I have found that certainconditions of reaction are particularly desirable. The-discovery ofthese reaction conditions actually constitutes an invention within aninvention, in that it makes possible the preparation of the mostdesirable products with the minimum of time and effort. In particular, Ihave found that reaction is promoted by passing through'the mixture,during reaction, a slow stream of oxygen or oxygencontainlng gas, suchas air. The beneficial effect of this operation appears to arisedirectly from the oxygen in the gas used. If nitrogen, hydrogen, orother inert oxygen-free gas is passed through. the reactionmixture, therate of reaction appears not to be appreciably increased.

J Whenoxygen or an oxygen-containing gas is passed through the reactionmixture, temperature may be maintained at any point over a rather widelimit; but as remarked above, I obtain best results using a temperatureof reaction in the range from about 150 C. to about 210. With reactantsthat boil within the temperature range, it is desirable that thematerials be reacted under pressure, or that the reaction be conductedfor a while at a lower temperature until esterification of the reactantshas produced an intermediate of higher boiling point. The temperaturemay then be gradually increased to a higher value, in order to increasethe rate of the reaction At extremely high temperatures, however, de-

composition and oxidation of the product may occur to an-objectionabledegree.

The time of reaction will depend, of course;

upon the reactants themselves and upon the temperature at which thereaction is carried 1 out, as well as upon the use to which the materialj is to be put. Ordinarily this time of reaction will 1 be severalhours, and perhaps as much as 48-72 hours. To prepare pour pointdepressants'I-have found that a typical set of conditions may involve 1a reaction temperature of about 200 C. and a 1 reaction time of about 24hours.

is to be used as a viscosity index improver, a

; materialof higher molecular weight is required example,

45 hours.

If the product .75 iodine No. (Wiis) of 16.9.

scribed in terms of their .preparation from three. 0 classes ofreactants, it should be pointed out that the reaction may be carried outin a series 'of steps. The first step might involve reacting only two,of the reactants; and this product then may be further reacted with thethird material. For in preparing a pour point depressant from reactantssuch as maleic anhydride, abietyl alcohol, and stearyl alcohol, themaleic anhydride and abietyl alcohol may be condensed first to give asemiresinous polmer ester of the type disclosed s in my aforementionedco-pending application Serial No. 489,237. This product may then bemixed with stearyl alcohol about equivalent to the free carboxylic acidcontent of the polymer,

.and further heated and esterifled to complete es- 2 'terification.Ordinarily, however, it is more convenient and simpler to. combine allof the reactants at once to prepare the desired compound.

The following examples will serve to illustrate the methods ofpreparation which may be em- 25 played. The parts are by weight Example1 17 parts of maleic anhydride, 45 parts of commercial oleyl alcohol(iodine No. 67) and 45 gms.

of commercial stearyl alcohol were heated and room temperature. It hadan average'molecular weight, as determined in benzol, of 1820. It wasclearly soluble in lubricating oil. The product had a finite, but low,acid value. 1

Example 2 v 14 parts of maleic anhydride and parts of commercial oleylalcohol were heated and stirred in a flask attached to a refluxcondenser. The temperature was held at 200 C. to 225 C. for 11 Themixture was then cooled and to it were added 26 parts of stearylalcohol. A water trap was placed between the flask and condenser andheating was resumed. The temperature was raised to 240 C. and held forthree 50 hours, after which time, water evolution had 0 ceased.

The product was a red, opaque syrup at room temperature. It apparentlycontained some unreacted stearyl alcohol. Its average molecular weightin benzol was 945,

Example .3 14.0 parts of maleic anhyride, 37.5 parts of commercial oleylalcohol and 37.5 parts of comso mercial stearyl alcohol were placed in aglass vessel equipped with stirrer, gas inlet tube, water trap, andcondenser. The mixture was heated while stirring t 175 C. and held fortwo hours. After that time, a slow stream of air was introduced throughthe, gas inlet. tube under the surwater were collected in the trap. Somewater was probably lost in the air stream. I v

The product was a light red, transparent,

waxyfsolid at room temperature. It was clear-' ly soluble in lubricatingoil. The product had an Example 4 14 parts of maleic anhydride, 37.5parts of commercial oleyl alcohol and 25 parts of com- 12.5 parts ofcommercial lauryl alcohol, 18.8 parts of commercial stearyl alcohol,37.5 parts of commercial oleyl alcohol, and 14.0 parts of maleicanhydride were reacted, using the apparatus and procedure of Example 3.I

The product was a viscous red oil having an iodine No. (Wijs) of 24.8.

Example 6 16.5 parts of fumaric acid were substituted for themaleicanhydride of Example 5. The product was substantially identical withthat of Example 5.

Example 7 20 parts of dihydroabietyl alcohol, 29 parts of commercialstearyl alcohol, 20 parts of commercial lauryl alcohol and 14 parts ofmaleic anhydride were reacted, using the apparatus and procedure ofExample 3.

The product was a viscous red oil.

Example 8 16.5 parts of fumaric acid were substituted for the maleicanhydride of Example '7. v

Example 9 Linoleyl alcohol was substituted for the oleyl alcohol inExample 5.

Example 10 16 parts of citraconic anhydride were substituted for themaleic anhydride of Example 5, and heating and stirring in the presence.of an air stream and at a temperature of 190,-195 C. was continued for36 hours.

It will be noted that in some of the above examples mixtures ofsaturated alcohol have been employed instead of a single species ofsaturated aliphatic alcohol. The use of such mixtures is considered theequivalent of using a single species of alcohol. If desired, mixtures ofunsaturated alcohol may also be employed, instead of one unsaturatedalcohol; and the same analogous condition applies to the use of the ccflunsaturated polycarboxylic acid,

Although it has been stated that the presen compounds are made from amixture of up unsaturated polycarboxylic acid and certain saturatedaliphatic alcohols and certain unsaturated aliphatic oralkylcycloaliphatic alcohols, in which the modes of alcohol areequivalent to the number of carboxylic acid groups present, it is notabsolutely necessary that the hydroxyl and carboxyl groups be exactlyequivalent. In fact, in some instances, it may be desirable to use asmall excess of unsaturated acid over that required to esterify all ofthe alcoholic hydroxyl groups. When this is done, the final product maymercial lauryl alcohol were heated and stirred of such reagent may beneutralized with alkalies or. amines or heavy metal oxides to yieldpolymeric salts which have useful properties in addition to those of thepolymers alone. For example, salts such as the sodium salts may be usedas sludge dispersers or detergents in lubricating oils. to inhibit theoxidation of lubricating oils. By theproper balance of carboxyl groupsto molecular weight, it is possible to prepare poly-functionallubricating oil additives, i. e., materials which have more than onefunction; for example, they may be both pour point depressants andantioxidants. In general, however, it is desirable that the number ofresidual carboxyls in the polymer product not be sufficient to give theproduct a neutralization equivalent of less than about 3,000.

Th nature of the reaction which results in the formation of the presentproducts is not clearly understood, but it is believed that the 043unsaturated polycarboxylic acid esterifies the hydroxyl groups of thealcohols and also adds, by proton transfer, to th unsaturated alcohol atan ethylenic carbon atom of same, or

at a carbon atom near the double bond. The

unsaturated alcohol undergoing condensation with a molecule of ethylenicacid is probably esterified by a different'molecule of ethylenic acid;so a type of linear polyester is formed. The saturated alcohol employedin the reaction mixture is also esterified by carboxyl groups of thepolybasic acid; the final product thus being a complicated type ofpolyester. When the double bond of the unsaturated alcohol is nearer tothe hydroxyl group than allowed by the conditions previously given, goodyields of the desired products do not seem to be obtainable. It isbelieved that this may result from the formation of stable cyclic inneresters, rather than linear polyesters. This postulated reaction may beexemplified, in part, by the reaction between oleyl alcohol, stearylalcohol and maleic acid. With these reactants it is believed that theproduct may b a polymerized, substituted, succinic acid ester, orpossibly, a polymerized, substituted, fumaric acid ester. Conceivablereactions are as follows:

' mHatOH nCmHmOH nolmo.

0 0 1sHa1 In the above formulae, no attempt has been made to define thecarbon atom of the oleyl alcohol residue to which the maleic acidresidue becomes attached. Probably, a carbon atom near the double bond,or a double bonded carbon atom itself, is involved. It becomesimpractical to attempt to show in detail all of the conceivablereactions of the above types which may occur.

The present products will be referred to herein and in the claims ascondensation polymers, this term being used in the sense as definedin-Gilman Organic Chemistry, 2nd edition, page 702. However, as pointedout above, their formation is believed also to involve addition of oneoleflnic molecule to another olefinic have a small acid number; and forcertain uses,

moleculathus, in the strictest sense, the result-.

ant compounds may be looked upon as being both condensation and additionpolymers.

Certain amine salts may be used I and, in fact, is an objectionable thepreparation reactions are carried out, as depounds contemplated havemolecular weights larger than the simple monomeric ester formed byesterification of the ethylenic polycarboxy acid with the alcoholreactants. As prepared, the crude products, in many instances, undoubtedly contain some monomeric ester as impurity. but such monomer is notcontemplated herein,=

scribed, the amount of monomer present is us- 1 f ually quitenegligible.

Because of the uncertainty as to the mecha- 1 nism of the reaction, aswell as to the large 1 variety of possible reactions which could bepostulated, no eifort will be made to describe j the present products interms of conventional 5 chemical formula.

My present invention consists in using prod- 1 nets of the kindpreviously described, to lower the pour point or increase the viscosityor vis- 1 cosity index of lubricating oils, or consists of 1 a newcomposition of matter, composed of a rel- .atively small amount of sucha condensation Qpolymer and a lubricating oil. are examples of my newcomposition.

Example I 0.25 gm. of the product of Example l was dissolved in 100 ml.of a 20 S. A. E. viscosity Gulf Coast lubricating oil- This mixture hada pour point of 25 F., in comparison with a pour point of 20 for theoriginal oil.

Example 11 The product of Example 3 was dissolved in varying proportionsin the lubricating oil of Example I. Pour points of the various mixturesare shown in the table below:

blends are shown below:

Concentra tion of 5232 prodliiilct in on Per cent F.

+20 it M2 -20 30 K; -30

Example III diluent. When The following 1 to an aliphatic alc saturatedalcohol densation polyme 1 taining at least 8 I Example IV The productof Example 3 Wasadded in the amount of 2% to 9. Gulf Coast lubricatingoil having a viscosity index of 55, The resulting blend was clear andlight in color and was found to have a viscosity index of 85.

In general,the percentage of the present compounds which will berequired to depress the pour point of oils sufiiciently to be ofpractical interest, will vary from as little as 0.025% to as much as1%,'or even 2%. The amounts required to increase the viscosity index byappreciable amounts will vary from as little as 0.25% to as much as 5%,or even more, depending upon the compound and the character of the oilto which it is added.

Thus, one object of my invention is the preparation of improvedlubricating oils or lubricating oil compositions a 0.025% or more thanabout 5% of the herein described compounds to lubricating oils which areused in an internal combustion engine or as lubricants for movingmachinery.

The present products are in general unsaturated, as reaction does notremove all of the olefinic groups of the unsaturated reactants. Ifdesired, these products may be hydrogenated to remove olefinic doublebonds. Other chemical reactions may also be employed to modify theproperties of the polymers. For example, they may be treated with sulfurat elevated temperatures to form sulfurizecl polymers; or they may betreated with chlorine to remove the unsaturation and otherwise modifytheir properties; or they may be treated with sulfur chloride to giveproducts of somewhat different properties. The introduction of sulfurinto the present compounds does not appear to change their pour pointdepressant properties, while at the same time it improves theirresistance to oxidation and also imparts to them film strength improvingproperties.

Previous reference has been made to the fact that one may employ eitheraliphatic or cycloaliphatic alcohols of the kind described. Although,ordinarily speakin aliphatic alcohols and alkylcycloaliphatic alcoholsare not necessarily the obvious equivalent of each other, yet in lightof what has been said above, it is obvious that they are the functionalequivalent in the present instance. In the hereto appended claimsreference ohol is intended to include the alkylcycloaliphatic alcohols.Reference to a straight chain alcohol must, of course, contemplate onlythe acyclic type.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patentis:

l. A composition of matter, comprising a lubricating oil and arelativelysmallamount of a (:13 unsaturated polybasic carturatedaliphatic alcohol conr;' said saturated alcohol conand not more than 32carbon having less than 10 carbon atoms boxylic acid-unsa atoms; saidacid and said unsaturated alcohol containing less than i 32 carbon atomsthe hydroxyl gr ent in an amo and having at least 3 intervening tweenthe carbon atom to which oup was attached and the nearest ethyleniccarbon atom; said polymer being presunt varying from 0.025% to aboutcarbon atoms be it is admixed.

2. A composition of brlcating oil and a re] matter, comprising a 111-atively small amount of a dding not less than abouton the basis of thelubricating oil with which saturated alcohol-up unsaturated polybasiccarboxylic acid-unsaturated aliphatic alcoholcondensation polymer; saidsaturated alcohol containing at least 8 and not more than 32 carbonatoms; said acid having less than 10 carbon atoms and said unsaturatedalcohol containing at least 8 carbon atoms and having at least 3intervening carbon atoms between the carbon atom to which the hydroxylgroup was attached and the-nearest ethylenic carbon atom; said polymerbeing present in an amount varying from 0.025% to about 5% n the basisof the lubricating-oil with which it is admixed.

3. A composition of matter, comprising a, lubricating oil-andarelatively small amount of a straight chain saturated alcohol-acunsaturated polybasic carboxylic acid-unsaturated aliphatic alcoholcondensation polymer; said saturated alcohol containing at least 8 andnot more than 32 carbon atoms; said acid having less than 10 carbonatoms and said unsaturated alcohol containing at least 8 carbon atomsand having at least 3 intervening carbon atoms between the carbon atomto which the hydroxyl group was attached and the nearest ethyleniccarbon atom; said polymer being present in an amount varying from 0.025%to about 5%, on the basis of the lubricating oil with which it isadmixed. I

4. Acomposition of matter, comprising a 111-- bricating oil and arelatively small amount of a straight chain saturated aICOhOI-afiunsaturated polybasic carboxylic acid-unsaturated straight chainaliphatic alcohol condensation polymer; said saturated alcoholcontaining at least 8 and not more than'32 carbon atoms; said acidhaving less than 10 carbon atoms and said unsaturated alcohol containingat least 8 carbon atoms and having at least 3 intervening carbon atomsbetween the carbon atom to which the hydroxyl groupwas attached and thenearest ethylenic carbon atom; said polymer being present in an amountvarying from 0.025% to about 5%, on the basis ofv the lubricating oilwith which it is admixed. i

5. A composition or matter, comprising a lubricating oil and arelatively small amount of a straight chain saturated alcohol-mpmonoethylenic polybasic carboxylic acid-unsaturated straight chainaliphatic alcohol condensation polymer; said saturated alcoholcontaining at least 8 and not more than 32 carbon atoms; said acidhaving less than 10 carbon. atoms and said unsaturated alcoholcontaining at least 8 carbon atoms and having at least 3 interveningcarbon atoms between the carbon atom to which the hydroxyl group wasattached and the nearest ethylenic carbon atom; said polymer beingpresent in an amount varying from 0.025% to about 5%, on the basis oithe lubricating oil with which it is admixed.

6. A composition of matter, comprising a lubricating oil and arelatively small amount or a straight chain saturated alcoholpmonoethylenic dibasic carboxylic acid-unsaturated straight chainaliphatic alcohol condensation polymer; said saturated alcoholcontaining at least 8 and not more than 32 carbon atoms; said acidhaving less than 10 carbon atoms and said unsaturated alcohol containingat least 8 carbon atoms and having at least 3intervening carbon atomsbetween the carbon atoms to which thehydroxyl group was attached and thenearest ethylenic carbon atom; said polymer being present in an amountvarying from 0.025% to about 5%, on the least 8 and not more than 32carbon atoms; said acid having less than 10 carbon atoms and saidunsaturated alcohol containing at least 8 carbon atoms and having atleast 3 intervening carbon atoms between the carbon atom to which thehydroxyl group was attached and the nearest ethylenic carbon atom; saidpolymer being present in an amount varying from 0.025% to about 5%, onthe basis of the lubricating oil with which it is admixed.

8. A composition of matter, comprising a lubricating oil and arelatively small amount or a straight chain saturated alcohol-maleicacid monoethylenic straight chain aliphatic alcohol condensationpolymer; said saturated alcohol containing at least 12 and not over 22carbon atoms, and said unsaturated alcohol containing at least 12 andnot over 22 carbon atoms and having atleast 3 intervening carbon atomsbetween the carbon atom to which the hydroxyl group is attached and thenearest ethylenic carbon atom;

said polymer being present in an amount varying from 0.025% to about 5%,on the basis or the lubricating oil with which it is admixed.

9. A composition of matter, comprising a lubricating oil and arelatively small amount of a straight chain saturated alcohol-fumaricacid monoethylenic straight chain aliphatic alcohol condensationpolymer; said saturated alcohol containing at least 12 and not over 22carbon atoms, and said unsaturated alcohol containing at least 12 andnot over 22 carbon atoms and having at least 12 and not over 22 carbonatoms and having at least 3 intervening carbon atoms between the carbonatom to which the hydroxyl group is attached and the nearer ethyleniccarbon atom; said polymer being present in an amount varying from 0.025%to about 5%, on the basis of the lubricating oil with which it isadmixed.

CHARLES M. ma.

